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Why Epigenetics is the Key to Memory and Learning (Pregnancy Edition)

Epigenetics, memory and learning, epigenetics and pregnancy

 

Recent scientific discoveries have been able to establish a direct link between memory and learning abilities, in young children, and epigenetic modifications during pregnancy. This knowledge is of profound importance to our global cultures and promises to revolutionize our family education, should we pursue the evidence wherever it may lead.

But, before we explore the scientific evidence, let’s me first begin with a question. Why do the trillions of cells that we carry in our body behave differently despite carrying the same genetic material? Why do some form brain cells and others form skin or liver cells?

Epigenetic Mechanisms

The human genome consists of approx. 3.2 billion basepairs, so then what makes them have different genetic expressions. [1] Now, this is an interplay of several mechanisms and one of them is known as epigenetics.

There are two important mechanism’ that plays critical roles in genetic expression: DNA Methylation and the other is Histone Modification. Both alter the genes expression without changing the gene sequence, and these changes can be inherited. DNA methylation occurs when certain methyl molecules bind to the DNA to switch on or off a particular gene. [2] It generally acts to repress gene transcription.

This process happens not just on the DNA sequence but occurs on the set of histones, and they can undergo various kinds of modifications [3] [4] This action occurs when an environmental signals, binds to the histone, that covers the DNA, and causes in to detach; enabling sections of your genetic code to be read or not. Again these modifications enable certain regions of DNA to be exposed and over expressed or under expressed. [5] 

So although all cells carry the same genes, these processes change what part of your genetic code is exposed, and ultimately determines which genes can make mRNA. So the sequence essentially remains the same but the mere presence of methyl molecules affects the expression of protein and this results in the formation of different organs. Through this process, you acquire epigenetic tags and develop an epigenetic profile. 

Epigenetics Marks During Pregnancy Effects Memory and Learning Functions in Young Children

Epigenetic modifications not only affects the chances to have disease but a recent study published in International Journal of Epidemiology provides new evidence that developmentally induced epigenetic tags during brain development is directly linked to a child’s cognitive performance and ability for memory and learning. [6]

Professor Karen Lillycrop and Dr Paula Costello from the University of Southampton with teams from New Zealand and Singapore studied the two parameters at these two different clinics and wanted to study the association between them. [7] This study looked at the umbilical cord tissue collected at birth and found epigenetic marks in a key brain development gene called HES1, that is linked to the ability to cognitive performance in children of between the ages of 4 and 7 years. They observed that certain methylation patterns, produced additional proteins that were directly correlated with a child’s ability to mesmerize and remember certain functions in later years. This cannot be done for all the genes and hence the marker gene used in the study was HES1 DMROI. The study suggested that methylation led to more expression of the protein and so HES1 inhibited ETS transcription factor binding, suggesting that differential methylation had a functional effect on HES1 expression.

Professor Keith Godfrey, a member of the research team from the University of Southampton comments “To date the main focus of research to identify what determines a child’s ability to learn has been on influences acting after birth. The strong links between epigenetic marks at birth and a child’s ability to learn point to a much greater influence of brain development before birth than previously recognised. Research is now making progress in defining how the mother’s lifestyle and emotional wellbeing during pregnancy can alter epigenetic processes in the baby before birth — in time this could lead to new approaches to diminish disparities in later school performance.”

So, the conclusion of the study was that having more of this protein enable the child in later years to have better memory and cognitive results than their counterparts. This is also the first time such a correlation has been found, and was observed for both the groups of children studied at the New Zealand clinic and also in Singapore.

What We Know …

It is now clear that environmental factors during pregnancy and onward, play a critical role in the genetic expression of learning and memory. However, what we do not know, and what requires a significant amount of research, is what environmental factors cause these genetic expressions in the first place. But, more importantly, research will explore how unfavorable genetic expression, that cause disabilities, in theory and practice, can be reversed.

Thus, for future educational programs, an important questions arises, in what kind of experimentation can be pursued to better understand the effects of our current family educational programs, on gene expression, so that we can improve the memory and learning abilities of future people.

In conclusion, environment and emotional health matters for your children’s educational performance, from pregnancy to adulthood and different epigenetic mechanism, change your genetic expression and capacity for memory and learning. That you can be sure about! Now, it’s up to scientist and public officials to fund innovative research to find out what environmental factors cause the genes to express themselves in positive ways and how unfavorable expressions can be reverse.

Stay tuned for follow up articles, for this series “Why Epigenetics is the Key to Memory and Learning”

References:

[1] http://www.ncbi.nlm.nih.gov/pubmed/11236992
[2] Uhlén et al (2015). Tissue-based map of the human proteome. Science PubMed:  25613900  DOI:  10.1126 /science.1260419
[3]Bhasin M, Reinherz EL, Reche PA (2006). “Recognition and classification of histones using support vector machine”. J. Comput. Biol. 13 (1): 102–12. doi:10.1089/cmb.2006.13.102PMID 16472024
[4] Marino-Ramirez L, Kann MG, Shoemaker BA, Landsman D (March 2007). “Histone structure and nucleosome stability”. Expert Rev Proteomics 2 (5): 11.doi:10.1586/14789450.2.5.719PMC 1831843PMID 16209651.
[5] Alva V, Ammelburg M, Lupas AN (March 2007). “On the origin of the histone fold”BMC Struct Biol 7: 17. doi:10.1186/1472-6807-7-17. PMC 1847821.PMID 17391511.
[6] Karen a Lillycrop, Paula M Costello, Ai Ling The, Robert J Murray, Rebecca Clarke-Harris, Sheila J Barton, Emma S Garratt, Sherry Ngo, Allan M Sheppard, Johnny Wong, Shaillay Dogra, Graham C Burdge, Cyrus Cooper, Hazel M Inskip, Catharine R Gale, Peter D Gluckman, Nicholas C Harvey, Yap-Seng Chong, Fabian Yap, Michael J Meaney, Anne Rifkin-Graboi, Joanna D Holbrook and Keith M Godfrey. Association between perinatal methylation of the neuronal differentiation regulator HES1 and later childhood neurocognitive function and behaviour. International Journal of Epidemiology, 2015 DOI: 10.1093/ije/dyv052
[
7] http://www.sciencedaily.com/releases/2015/04/150422220554.htm 

 

 

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    By: Dr. Suhasini Bhatnagar

    Dr. Suhasini Bhatnagar has done her PhD in Medical Genetics and sub specialization of human population genetics from the Sanjay Gandhi Postgraduate Institute of Medical sciences in 2001.For this she had her GATE percentile 96.8 and was UGC-NET qualified.She has more than 15 international publications and has attended one International Conference and several National Conferences.She did her post graduation in Biotechnology from The M.S.University of Baroda in 1992 for this she got the deptt. of Biotechnology fellowship.She was awarded Fellowship by DBT for pursuing M.Sc in biotechnology.She was granted CSIR-JRF NET fellowship Council of Scientific and Industrial research.She had done her graduation from Botany (Hons.) in 1990 from Gargi College.She was awarded The Prativa Mukherjee Award for securing highest marks in Botany in 1987.She has a teaching experience of more than 8 years and research experience of 9 years.

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